1. Field of the Invention
The present invention relates to an underwater tracking system and more particularly to an underwater tracking system using inertial measurement techniques.
2. Description of the Prior Art
Underwater tracking ranges are used throughout the world to facilitate the research, engineering, test and evaluation of underwater vehicles. Traditionally, the task of tracking underwater vehicles has been accomplished using underwater acoustic triangulation systems. In these systems acoustic pulses are transmitted from the underwater vehicle and received by a plurality (usually four) of underwater hydrophones. By measuring arrival time of the acoustic pulse at these hydrophones the position of the vehicles can be calculated. Although the performance of acoustic tracking systems is at most times adequate, limitations exist which preclude the effective adaptation of acoustic triangulation technology to advanced ranging requirements. For example, acoustic triangulation systems have proved to be too expensive for large area tactical ranges. These systems also have cost and technical limitations which deter their effective utilization in shallow water ranges. Moreover, the requirement of a relatively large number of accurately located hydrophones precludes their effective use in portable range systems.
The present invention overcomes these problems by providing a highly effective, low cost underwater tracking system using an inertial measurement system on the underwater vehicle. This eliminates the need for precisely located fixed underwater sensors since all of the information concerning vehicle location is being measured on the vehicle and may be transmitted to a single hydrophone.